This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Very increased levels of the mineral phosphorus, and low level of the protective cholesterol fraction high density lipoprotein (HDL) cholesterol are found commonly in patients with chronic kidney disease (CKD) contributing to heart disease, including fatal heart disease, and the progression of CKD to kidney failure. Current daily phosphorus lowering treatments require the intake of multiple pills three times daily, a burden which negatively affects patient compliance and quality of life. Niacin compounds, including slow release once daily products, lower serum phosphorus levels, and raise HDL levels in patients with kidney failure. We plan to assess the effect of a once daily oral niacin product on serum phosphorus levels in patients with less advanced CKD, before such patients might develop kidney failure. This information will help us evaluate niacin's potential as a simple, inexpensive, and well-tolerated treatment to lower elevated phosphorus in patients with kidney disease. Eventually, niacin may be considered as an agent to reduce the risk for heart disease and progression to kidney failure in these patients.